Groundnut (Arachis hypogaea L.) is a member of family Fabaceae. It is an important monoecious annual legume, mainly grown for oilseed. Gamma irradiation is a powerful tool to induce genetic alteration and improvement in crops with beneficial mutants. The study was undertakenn to evaluate the quantitative traits of gamma rays on groundnut. Genetically healthy, dried and uniform size seeds of groundnut variety of Dharani were treated with six doses viz., 100, 200, 300, 400, 500 and 600 Gy of gamma rays. The biological damage based on lethality and injury was estimated in the M1 generation. The present investigation reveals that seed germination LD50 value recorded at 300 Gy and highest survival percentage value was obtained at 100 Gy compared to control and other treatments. In M1 generation, the morphological and quantitative traits were decreased as the dose increases. The maximum reduction was observed at 600 Gy. In general, the higher doses showed increasing plant damage compared to control. The amino acid content was high in 500 Gy doses of gamma irradiation. The lipids, protein and carbohydrate content were high in 400 Gy compared to control and other doses. Gas chromatography-mass spectrometry (GC-MS) was used to analyse the lipid substances and the results showed that significantly more compounds were found in seeds that had received 400 Gy radiation than in untreated seeds. The current study found that gamma irradiation changes the morphology, quantitative characteristics and biochemical composition of groundnut seeds in the M1 generation.